Answer:
The Sahel is the ecoclimatic and biogeographic zone of transition in Africa between the Sahara to the north and the Sudanian Savanna to the south. Having a semi-arid climate, it stretches across the south-central latitudes of Northern Africa between the Atlantic Ocean and the Red Sea. Wikipedia
Area: 1.179 million mi²
The Sahel has a tropical, hot steppe climate (Köppen climate classification BSh). The climate is typically hot, sunny, dry and somewhat windy all year long. The Sahel's climate is similar to, but less extreme than, the climate of the Sahara desert located just to the north.
Explanation:
Yes because rivers are important for trade and even things like fresh water and transport.
The lowland areas of Latin America are very important because of multiple reasons. The majority of the agriculture and farming of animals is taking place in the areas like this, so the food sector is directly connected with them. On top of the agricultural production, these lowlands produce a lot of food on their own. The industries that use as their main material also are directly dependent on these lowlands, as they are mostly covered with numerous types of high quality tropical tree species. There's thousands of species of plants that are used in the medicine, so the pharmacies are also very dependent on them. All in all, these lowlands managed to contribute a lot in the economy, health, and general well being of the Latin American countries.